There are many situations where is it desirable to locate buried utilities such as pipes and cables. For example, prior to starting any new construction that involves excavation, it is important to locate existing underground utilities such as underground power lines, gas lines, phone lines, fiber optic cable conduits, CATV cables, sprinkler control wiring, water pipes, sewer pipes, etc. If a back hoe or other excavation equipment hits a high voltage line or a gas line, serious injury and property damage can result. Severing water mains and sewer lines leads to messy cleanups. The destruction of power and data cables can seriously disrupt the comfort and convenience of residents and cost businesses huge financial losses.
Buried objects can be located by sensing an electromagnetic signal emitted by the same. Some cables such as power lines are already energized and emit their own long cylindrical electromagnetic field. Location of other conductive lines necessitates their energizing with an outside electrical source having a frequency typically in a range of approximately 50 Hz to 500 kHz. Location of buried long conductors is often referred to as “line tracing.”
In the typical locating operation, an operator will use a portable electronic locator to determine the underground location of a buried utility, sonde, or like object, and will then use an aerosol paint can to mark on the surface of the ground the apparent location of the buried object that has been located. In this way, the location of existing underground utilities can be known to an excavator and can be avoided during excavation, preventing expensive damage and potential personal injury. However, existing locators heretofore have not made it convenient to both locate a buried utility and mark its location on the ground. The conventional approach interrupts the locate process as a result of the necessity of picking up an aerosol paint can and applying paint on the ground to mark a location of a buried pipe or conductor that has been located. This adds time to the locate process, reducing productivity. It also imposes the necessity of stooping or bending in order to apply markings. This interruption also causes the operator to take his or her attention away from the instrument being used to detect the buried utility, thus introducing the risk of an inaccurate marking.
Separately held tools have been developed for holding an aerosol paint can and operating it from a standing position. See for example U.S. Pat. No. 5,368,202 of Smrt. Such stand alone marking paint applicators must be carried and handled separately from the locator. One prior art locator has been designed with a marking paint applicator embedded permanently into its structure. See U.S. Pat. No. 6,723,375 of Zeck et al.